A reactor is one of parts in a circuit that performs a step-up operation and a step-down operation of a voltage. The reactor is used for a converter mounted on a vehicle such as a hybrid electric vehicle. For example, the reactor is disclosed in Patent Literature 1.
The reactor disclosed in Patent Literature 1 includes a coil having a pair of coil elements, and a ring-shaped core for a reactor (a magnetic core) including a pair of coil arranging portions covered with these coil elements and a pair of exposed portions which is not covered with the coil elements. The coil arranging portion is made of a powder compact, a hardened compact obtained by hardening a resin of a mixture (a composite material) of magnetic powder and a resin having fluidity or the like. The exposed portion is made of a powder compact.